The invention is based on a drill—and/or chipping hammer.
Drill—and/or chipping hammers having a striking mechanism are known that comprise a drivable pot-type piston having at least one idle opening.
If the drill—and/or chipping hammer is pressed—with a tool—against a surface to be worked, a striker moves in the direction of the idle opening, so that, in a working position, a rear edge of the striker covers the idle opening. This closes said idle opening, and an air cushion located in the pot-type piston is compressed by means of an axial motion of the pot-type piston in the direction of operation and by means of inertia of the striker that is moveable in the pot-type piston. When the compressed air cushion expands, the striker is accelerated in the direction of a tool mount and strikes a punch dolly that drives a tool situated in the tool mount.
When a short structural design is involved, in order to prevent the idle opening from opening uncontrollably in the working position, the idle opening would be ideally located—in the axial direction—in an anterior region of the pot-type piston closest to the tool mount, so that, during operation in the striking mode, the rear edge of the striker or the striker itself always keeps the idle opening closed and it is prevented from opening unintentionally.
When a short structural design is involved, in order to ensure reliable and rapid opening of the idle opening with few idle strokes of the striking mechanism when an idle position is reached, the idle opening—on the other hand—would be ideally located—in the axial direction—in a posterior region of the pot-type piston furthest away from the tool mount, so that the rear edge of the striker is always located in front of the idle opening in the direction of a base of the pot-type piston, and said idle opening remains open at all times.
In order to fulfull both objectives to the greatest extent possible, the idle opening is located—in practice—in a position between the two individual ideal states.